February 2007
Intermediate to advanced
464 pages
14h 40m
English
This chapter covered the basics of time-frequency analysis techniques for audio signal processing and coding. We also highlighted the time-frequency tradeoff challenges faced by the audio codec designers when designing a filter bank. We discussed both the QMF and CQF filter-bank designs and their extended tree-structured forms. We also dealt in detail with the cosine modulated pseudo-QMF and perfect reconstruction M-band filter-bank designs. The modified discrete cosine transform (MDCT) and the various window designs were also covered in detail.

Figure 6.25. Temporal noise shaping example showing quantization noise and the input signal energy envelope for castanets: (a) without TNS, and (b) with TNS.